This training program is designed to train dermatologists who desire a thorough grounding in the following broad disciplines: biochemistry, cell biology, enzymology, epidemiology, genetics, immunology, microbiology, molecular biology, morphology, and photobiology; or Ph.D.'s who desire experience in biomedical problems involving skin. We are also requesting for the first time one (1), one year predoctoral training position for students enrolled in the M.D. program who wish to postpone their studies for one year to gain research experience. The basic aim of training to provide an environment in which outstanding fellows can learn to be independent researchers in cutaneous biology. The thrust of our postdoctoral research training is that committed individuals spend a minimum of 2 years in a basic research laboratory and receive general and specialized instruction in the techniques of the laboratory by working on well deemed problem with one or more of the trainers. During this time they are spared from any significant clinical involvement. Trainees can choose from one of the following research areas; cell adhesion, cell proliferation and differentiation, proteinases and their inhibitors, intrinsic and photoaging, cutaneous T- cell lymphoma, pigmented lesions, wound healing, cutaneous microbiology, and gene therapy. Trainees interact predominantly with one investigator, but often are exposed to other laboratories due to the nature of the existing collaborations. Although a diversity of research areas exist in the Department of Dermatology, collaboration between trainers is the role, rather than the exception. Over the past 5 years we enrolled 9 men and 1 woman. Of these 10 trainees, 1 held the M.D. degree, 3 were M.D., Ph.D.'s and 6 held Ph.D.'s. The usual M.D. trainee will have 3 years of dermatology training before admission to this program, although in some instances, physicians have spent 2 years on the Training Grant prior to beginning a residency in dermatology. A Ph.D. trainee is usually admitted immediately after receiving his/her degree. Individuals with the combined M.D., Ph.D. have had 3 years of dermatology training, and are admitted to the Training Grant for the purpose of updating their investigative skills. Candidates are carefully selected to include those who have shown considerable interest and commitment to dermatological research and desire to continue in academic dermatology. The primary training facility is the 10,800 square foot Dermatology Research Laboratories, located on the second floor of the Clinical Research Building, and the 3,500 square foot Dermatology Research Laboratories on the Mezzanine of the Stellar-Chance Building of the University of Pennsylvania. Within these facilities there are 12 four hundred square foot individual laboratories, 12 one hundred square foot offices, and core facilities for administrative support, tissue culture, electron microscopy, dish washing and sterilization, and seminars.